A network of communication stations can share a communication medium (e.g., wires connecting multiple stations or spectrum for transmitting radio signals among stations) using any of a variety of access techniques. Some access techniques (e.g., carrier sense multiple access (CSMA) techniques) include a contention period in which stations contend for use of the medium for transmitting a signal by sensing when the medium is idle. In CSMA techniques, “collisions” sometimes occur when signals from two or more stations overlap. Some channel access techniques can also provide a contention free period in which a specific station or stream is provided exclusive control of the medium. Channel access techniques are used to provide varying levels of Quality of Service (QoS). For example, contention based channel access may be used to provide best-effort service while contention free channel access may be used to provide guaranteed QoS (bandwidth, latency, jitter and packet loss probability). Stations can have traffic flows that are intended for different destination and with varying levels of QoS requirements. Providing separate channel access for each traffic flow is inefficient due to the overhead required for each channel access. However, providing a single channel access for all traffic flows intended for the same destination results in degradation of Quality of Service.